vendor: bump tcptracer-bpf

[iaguis]

This includes:

• an eBPF object built with a newer kernel (4.14)
• an increased threshold for guessing offsets, which is necessary for
  the eBPF tracer to work on Google's Container-Optimized OS (used by
  GKE)

Fixes #2796

[rade]

an eBPF object built with a newer kernel (4.14)

What was the previous one built with?

What do we gain by the change?

Any compatibility issues?

[iaguis]

I started a 1.8.6 GKE cluster and deployed scope built with this PR to it. It seems to work fine:

$ kubectl version 
Client Version: version.Info{Major:"1", Minor:"9", GitVersion:"v1.9.0", GitCommit:"925c127ec6b946659ad0fd596fa959be43f0cc05", GitTreeState:"clean", BuildDate:"2017-12-15T21:07:38Z", GoVersion:"go1.9.2", Compiler:"gc", Platform:"linux/amd64"}
Server Version: version.Info{Major:"1", Minor:"8+", GitVersion:"v1.8.6-gke.0", GitCommit:"ee9a97661f14ee0b1ca31d6edd30480c89347c79", GitTreeState:"clean", BuildDate:"2018-01-05T03:36:42Z", GoVersion:"go1.8.3b4", Compiler:"gc", Platform:"linux/amd64"}
$ kubectl -n=weave logs weave-scope-agent-2tqx2
time="2018-01-26T13:36:24Z" level=info msg="publishing to: weave-scope-app.weave.svc.cluster.local:80" 
<probe> INFO: 2018/01/26 13:36:24.565466 command line args: --mode=probe --no-app=true --probe.docker=true --probe.docker.bridge=docker0 --probe.kubernetes=true weave-scope-app.weave.svc.cluster.local:80
<probe> INFO: 2018/01/26 13:36:24.565645 probe starting, version 9f3e7d3d, ID 503738f382bbe4de
<probe> INFO: 2018/01/26 13:36:25.233349 kubernetes: targeting api server https://10.11.240.1:443
<probe> WARN: 2018/01/26 13:36:25.323077 Cannot resolve 'scope.weave.local.': dial tcp 169.254.123.1:53: getsockopt: connection refused
<probe> WARN: 2018/01/26 13:36:25.326320 Error collecting weave status, backing off 10s: Get http://127.0.0.1:6784/report: dial tcp 127.0.0.1:6784: getsockopt: connection refused. If you are not running Weave Net, you may wish to suppress this warning by launching scope with the `--weave=false` option.
<probe> WARN: 2018/01/26 13:36:25.329714 Error collecting weave ps, backing off 20s: exit status 1: "/usr/bin/weave: line 261: docker: not found\nERROR: Unable to parse docker version\n". If you are not running Weave Net, you may wish to suppress this warning by launching scope with the `--weave=false` option.
<probe> ERRO: 2018/01/26 13:36:25.345911 conntrack stderr:NOTICE: Netlink socket buffer size has been set to 8388608 bytes.
<probe> INFO: 2018/01/26 13:36:25.372591 cronjobs are not supported by this Kubernetes version
<probe> ERRO: 2018/01/26 13:36:25.888734 Error fetching app details: Get http://10.11.250.93:80/api: dial tcp 10.11.250.93:80: getsockopt: connection refused
<probe> ERRO: 2018/01/26 13:36:27.898776 Error fetching app details: Get http://10.11.250.93:80/api: dial tcp 10.11.250.93:80: getsockopt: connection refused
<probe> ERRO: 2018/01/26 13:36:29.896710 Error fetching app details: Get http://10.11.250.93:80/api: dial tcp 10.11.250.93:80: getsockopt: connection refused
<probe> INFO: 2018/01/26 13:36:32.903156 Control connection to weave-scope-app.weave.svc.cluster.local starting
<probe> INFO: 2018/01/26 13:36:34.316470 Publish loop for weave-scope-app.weave.svc.cluster.local starting
<probe> WARN: 2018/01/26 13:36:35.330659 Error collecting weave status, backing off 20s: Get http://127.0.0.1:6784/report: dial tcp 127.0.0.1:6784: getsockopt: connection refused. If you are not running Weave Net, you may wish to suppress this warning by launching scope with the `--weave=false` option.
<probe> WARN: 2018/01/26 13:36:45.333296 Error collecting weave ps, backing off 40s: exit status 1: "/usr/bin/weave: line 261: docker: not found\nERROR: Unable to parse docker version\n". If you are not running Weave Net, you may wish to suppress this warning by launching scope with the `--weave=false` option.
<probe> WARN: 2018/01/26 13:36:55.375934 Error collecting weave status, backing off 40s: Get http://127.0.0.1:6784/report: dial tcp 127.0.0.1:6784: getsockopt: connection refused. If you are not running Weave Net, you may wish to suppress this warning by launching scope with the `--weave=false` option.

You can try my image:

$ kubectl -n=weave get pod weave-scope-agent-2tqx2 -o jsonpath="{..image}" | cut -f1 -d " "
kinvolk/scope:iaguis-update-tcptracer-bpf-9f3e7d3d

[iaguis]

What was the previous one built with?

We were building with whatever Fedora 25 has. Currently it's 4.13.16.

What do we gain by the change?

The change is there because weaveworks/tcptracer-bpf#52 got merged, which updates the docker image used to build tcptracer-bpf to Fedora 26.

We might get better code if the version of clang in Fedora 26 is newer, but nothing else.

Any compatibility issues?

Not that I know of, since we use the offset guessing code it shouldn't matter what version is used to build the eBPF object nor what version the code runs on.

[rade]

You can try my image

I have tested this in my existing GKE cluster, and it all works fine.